Gold Research Articles

Coordination Complexes of Copper, Silver and Gold with SNO Group Containing Thiosemicarbazones Schiff Base Ligands and their Biological Applications

The thiosemicarbazone Schiff base ligand is very important segment for chemistry, more specifically coordination chemistry. These compounds and their complexes widely used as medicinal agents for different lethal diseases such as cancer and other contagious disease caused by bacteria. The coordinated metal (coinage) complexes exhibited higher activities than free ligand for all the biological investigation of anticancer and antibacterial activities. The TSCs ligands having polydentate S-N-O coordinating sites. The mode of coordination of these ligands is flexible, it can act as tridentate or bidentate ligand. These ligand form mostly square planar complexes with copper, silver and gold metal ions. This research content could guide to identify the synthesized biomaterial. In this review, copper, silver, gold complexes are comprehensively summarized, and their activities and mechanism are documented. This review will provide very cut-edge guide of TSCs and their complexes to use in different field.

Analysis of Nature, Constituents and Effects of Navapashanam- Based on Facts of Siddha, Ayurvedic and Life Sciences- An Elixir of Life

Abstract: Navapashana, an ancient Ayurvedic formulation composed of nine specific elements, holds significant reverence in traditional medicinal practices. This study delves into the intricate nature, constituents, and perceived effects of Navapashanam, shedding light on its traditional significance and potential health benefits. The composition of Navapashanam comprises a blend of metals—gold, silver, copper, iron, lead, zinc, tin, mercury—alongside herbal extracts or natural substances. These ingredients undergo meticulous purification processes, involving grinding, heating, and amalgamation with herbal extracts, to create a purportedly potent elixir. Traditionally believed to confer diverse health advantages, Navapashana's effects encompass several areas. Advocates claim its potential in enhancing vitality, longevity, and immune function. Additionally, it is purported to detoxify the body, foster rejuvenation, and harmonise the body's energy systems or doshas, as per Ayurvedic principles. However1, caution is paramount due to the presence of heavy metals in Navapashanam, known for their potential toxicity. Despite sophisticated preparation methods aimed at rendering these substances safe, there exist safety concerns and associated risks. Therefore, the use of Navapashanam should be guided by experienced practitioners well-versed in its preparation techniques and safety protocols.This analysis underscores the historical significance, constituents, potential effects, and safety considerations associated with Navapashana, emphasising the necessity of expert guidance and caution in its utilisation for therapeutic purposes. Ultimately, a comprehensive understanding of Navapashana's complexities is crucial to assess its suitability and mitigate potential risks when considering its incorporation into traditional healthcare practices.

Jiangxi Copper Group Remuneration Policy Study

China's copper industry is an important industry in the national economy, with 91% of 124 industries related to copper. Jiangxi Copper Group has the highest self-sufficiency rate of copper concentrate in China, and is the largest and most modern copper production and processing base in China, and an important production base for gold, silver, selenium, tellurium, rhenium and other rare precious metals, and sulfur chemical industry. 1997, Jiangxi Copper Corporation was listed on the Hong Kong stock market, and in 2008, the management bodies of Jiangxi Copper Group Company and Jiangxi Copper Corporation were merged into a single one, and the company was listed as a whole. In 2008, Jiangxi Copper Group Corporation and Jiangxi Copper Corporation realized the merger of their management bodies into one, realized the overall listing, and established a modern management system and operation mechanism with the division system as the basic framework. This paper analyzes the remuneration policy of Jiangxi Copper Group by studying the remuneration status of its executives and employees, and compares it with other companies in the same industry to put forward development suggestions.

The genetic link between lode and disseminated gold ores and relationship between hypozonal and mesozonal deposits: A case study of the Yanzigou orogenic gold deposit, northwestern Yangtze Craton, China

The process controlling the formation of orogenic lode and disseminated gold ores is the basis for understanding the complexity of the orogenic gold system. The mesozonal Yanzigou gold deposit, located in the Danba ore district of the northwestern Yangtze Craton, is hosted by Devonian carbonaceous slate with coexisting fault-hosted lode and strata-bound disseminated gold ores. Three types of pyrite (PyI-q, PyII-q and Pyd) were formed during two stages of hydrothermal evolution. PyII-q in quartz-polymetallic veins and the rims of Pyd in disseminated ores have the highest Au and As contents, contrasting to distal sedimentary pyrite that have low Au and As contents. This implies that the Devonian host sequences are incapable of providing ore elements to the ore fluid. Pyd and associated quartz have intermediate isotopic values (δ34S = -1.7∼+0.8 ‰; δ18OH2O = 10.6 ∼ 12.7 ‰) between the quartz-vein ores (δ34S = 8.5 ∼ 10.7 ‰; δ18OH2O = 9.0 ∼ 10.1 ‰) and wall-rocks (δ34S ≈ −5‰; δ18OH2O ≈ 12 ‰), implicating a critical role of fluid-rock reaction in the formation of the disseminated gold ores and preservation of original ore fluid characteristics in the lode gold ores. The 40Ar/39Ar dating of hydrothermal muscovite from auriferous quartz veins at Yanzigou yields a total fusion age of 118.4 ± 0.4 Ma, later than ∼ 185 Ma for the nearby hypozonal Danba gold deposit. However, both deposits have common geological, geochemical, and isotopic signatures, suggesting a multi-stage orogenic gold mineralization on the Mesozoic dome margins associated with episodic reactivation of metasomatized mantle lithosphere during the continued crustal uplift.

Nucleation Behavior and Growth Characteristics of Atomic-Layer Deposited Iridium Thin Films with Ticp and Oxygen

Platinum group elements (Pt, Ru, Pd, Rh, Ag, Au, and Ir) have excellent properties of high thermal and chemical stability, and low electrical resistivity. Due to the attractive characteristics, these materials are also expected for applications in the semiconductor industries. In particular, iridium (Ir) has attracted interests as a potential electrode for memory devices because of its high work function and low resistivity (bulk: 4.7 μΩ cm).Despite the advantages of Ir, the deposition of Ir thin films for the next-generation memory applications faces critical challenges. Since metal has a high surface energy, it is difficult to adsorb on a surface with a lower surface energy. So, formation of metal nuclei is delayed in the initial growth of atomic layer deposition (ALD), and island growth is preferred. During the ALD, sparsely grown nuclei cause an increase in surface roughness which deteriorates the leakage current properties of capacitors.In this study, we attempted ALD of Ir films from newly synthesized tricarbonyl (1,2,3-η)-1,2,3-tri(tert-butyl)-cyclopropenyl iridium and oxygen. The growth behavior and film properties of impurity contents and bulk resistivity were investigated in terms of the growth temperature. Also, we examined the changes in the surface morphology of the iridium film with the film thickness. Consequently, we achieved the growth of continuous and smooth Ir films even below 4 nm by forming nucleation-promoting layer at high temperature and followed by ALD of Ir at low temperature. In addition, the capacitor device characteristics were also investigated using Ir as a bottom electrode.

(Invited) Direct Laser Induced Gold Wiring of 2D Materials with Sub-Μm Resolution

One of the most influential technologies of our modern world are integrated electronics. Almost all parts of our daily life include some bearing with any kind of electrical technologies. The fabrication methods itself, for integrated miniatured electrical devices have had not much innovation in terms of production. Several processing steps still mainly consist of different kinds of lithography. This situation may change with new challenges on the production of smaller quantities with specialized functions, or the use of temperature critical or atomically thin surfaces, where the thermal evaporation of metals damages the sample.For some decades now, printing of all types of electronics have gained great attraction. While lithography is a time-consuming multi-step process (including resist preparation, illuminating, developing, evaporation and lift-off) with expensive and harmful photoresists and harsh environmental conditions (high-vacuum and thermal treatments), ink printing allows for direct and simple application of the desired structures [1]. Two main types of inks are typically applied: colloidal solutions of metal nanoparticles [2, 3] or metal-organic precursor solutions [4]. In both cases, thermal curing after deposition is required to achieve metallic conduction. To this end, laser writing is often advantageous over thermal sintering due to the overall lower thermal stress applied to the material, particularly on flexible, thermally sensitive substrates [5] whereas metal nanoparticles suffer from a relatively high photothermal stability and the need for a large laser power to achieve sufficient sintering [3]. In contrast, metal-organic precursor solutions feature a relatively low metal content (≤34 wt-%)10, and undergo large volume contractions during laser writing. These challenges have so far prevented the definition of metallic gold contacts with diffraction-limited feature sizes by ink printing and laser writing.Here, we introduce atomically-precise, metalloid Au32(nBuP12Cl8) nanoclusters (Au32NCs) [6] as an ink for resistless, direct laser writing of metallic gold micro- and nanostructures. The unique advantages of this ink over Au nanoparticles or typical metal-organic Au precursors are their high photosensitivity in combination with a large gold content of 70 wt-%. This allows for writing gold structures with feature sizes of 250 nm and line spacings < 200 nm using 1.86 mW laser power at 488 nm with a scan speed of 0.1 mm/s. We apply this method on a wide range of substrates, including flexible polymer membranes, find metallic conductance with conductivities ~ 1 × 106 S/m and demonstrate that defining such Au contacts on two-dimensional semiconductors results in fully functional optical switches and field effect transistors made out from 2D materials.[1] Raut NC. et al., Jour. Mat. Chem. C 2018, 6(7): 1618-1641.[2] Ko E. et al., Nanotechnology 2007, 18(34): 345202.[3] Hong S. et al., ACS Nano 2013, 7(6): 5024-5031.[4] Schoner C et al., Thin Solid Films 2013, 531: 147-151.[5] Skylar-Scott MA et al., PNAS 2016, 113(22): 6137-6142.[6] Kenzler S et al., Angew. Chem. Int. Ed. 2019, 58(18): 5902-5905. Figure 1

Combining novel theoretical and experimental insights into the physical electrochemistry of gold and carbon-based electrodes and baicalein flavonoid sensing

Here, both the theoretical and experimental behavior of the flavonoid baicalein (BAI) was evaluated, considering the physical electrochemistry of carbon materials. For this purpose, experimental data based on cyclic voltammetry (CV) measurements were collected using the glassy carbon electrode (GCE) in comparison with a metallic gold electrode (GE). From a theoretical point of view, the focus was on modeling the BAI interaction with substrates through the use of graphene (its functionalizations) and a gold closed-packed slab model to understand the molecular adsorption process and verify important issues related to the analyte-substrate interaction at the atomistic level. The high-level quantum-mechanical calculations were based on density functional theory (DFT). From an analytical point of view, GCE and GE were tested for method development using differential pulse voltammetry (DPV). Regarding analytical purposes, limit of detection (LOD) values of 31.5 nmol L−1 and 68.1 nmol L−1 were estimated for GCE and GE, respectively. The standard addition method was explored with GE, while an external calibration curve approach was applied to overcome surface saturation on GCE. We found two elucidating points that may compromise electroanalysis: (i) in physisorption, the analyte adsorption occurs in parallel orientation to both substrate types, carbon- and gold-based ones, which compromises the useful electrode area; and (ii) in chemisorption, the presence of defects on the carbon-based electrode surface is responsible for a strong interaction that leads to BAI dissociation and electrode poisoning. Thus, the theoretical results support the mechanistic investigation, and novel insights into the electrochemical sensing of flavonoids are presented here.

Biooxidation of refractory silver minerals as pretreatment for silver recovery

The worldwide demand for silver is increasing due to the technological development in different areas, especially for the requirements in the production of renewable energies; therefore, for the treatment of refractory minerals by conventional processes, it is necessary to study mechanisms to identify the viability of their processing and the feasibility of their recovery, ensuring profitability. Gold and silver present in the matrix of sulfide-based ores are not affordably recovered by the conventional method involving leaching in sodium cyanide solution. Therefore, it must be subjected to oxidation pretreatment or conversion of the sulfides to simple compounds that allow recovery of the precious metals. The methods of oxidation of minerals considered refractory are carried out by hydro and pyrometallurgical methods, seeking the dissolution of sulfur, iron, arsenic and other elements present. It is important to identify and consider the mineralogical structure, microbiological variety, physicochemical characteristics, types of reactors, bacterial interactions, among other factors. The choice of biooxidation as the preferred process in projects for the recovery of gold, silver, copper or other metals, in most cases is based on the economic advantage, compared to the conventional processes of roasting, chemical leaching and pressurized leaching. The biooxidation of refractory argentiferous ores has been extensively studied in recent years, concluding that its application is feasible, mainly because it is environmentally friendly.

A novel insight into Au-Au thermosonic flip chip joint under extreme thermal cycles: Defect characterization and failure analysis

Au-Au thermosonic flip chip joints are regarded as a promising chip-substrate interconnect structures and their reliability has been a concern. Compressing the top of Au stud bumps during the coining process would result in plastic deformation of Au; During the bonding process, plastic deformation took place at the interface of Au stud bump and substrate under the impact of ultrasonic vibration, elevated temperature, and bonding pressure; additionally, due to different Coefficient of Thermal Expansion (CTE) between various components of the joint, the mismatch of CTE caused by the thermal cycling process would also result in plastic deformation. For Au element with extraordinary ductility, plastic deformation would inevitably lead to various material defects. This research first performed thermal cycling tests on Au-Au thermosonic flip chip joints, and found that a crack developed after 500 cycles and it propagated along the interface to the entire width of the joint, which seriously injured the joint. Here, for the first time, this research characterized all types of material defects (dislocations, stacking fault, twin, and amorphization) at the bonding interface of the Au-Au flip chip joint which underwent 500 thermal cycles. Their causes and effects on cracking were investigated individually, finally a novel failure mechanism was proposed from the perspective of material defects and a technique to prevent cracking was proposed. This research is anticipated to provide an in-depth study of the microstructure at the bonding interface of Au-Au flip chip joints and the impact of various defects on their reliability.

Phytosynthesizing gold nanoparticles: Characterization, bioactivity, and catalysis evaluation

Worldwide health problem generally due to the lack of widespread and comprehensive early detection methods, the associated poor prognosis of patients diagnosed in later stages of the disease and its increasing incidence on a global scale. Indeed, the struggle to fight cancer is one of the greatest challenges of mankind. Centella Asiatica (CA) and Andrographis Paniculata (AP) are two medicinal plant extracts used in the environmentally friendly extracellular production of metallic gold nanoparticles. The size, shape, stability and crystallinity of the synthesized gold nanoparticles were characterised and various characterization methods were used; UV–Vis spectroscopy, Fourier Transform Infrared Spectroscopy, X-ray diffraction, Zeta potential, Selected Area Electron Diffraction, Energy Dispersive X-ray Spectroscopy, High Resolution Transmission Electron Microscopy equipped with elemental mapping in order to confirm the formation of gold nanoparticles. The TEM results showed that gold nanoparticles were mostly spherical in shape. Their effects on anti-bacterial, catalytic, photocatalytic and anticancer cell lines were examined. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test was used to confirm the cytotoxic properties of both gold nanoparticles samples and the results showed that both the human lung cancer and human breast cancer cell line growth and proliferation were inhibited. Strong antibacterial activity against gram-negative bacteria and moderate antibacterial activity against gram-positive bacteria were identified. It has also been shown that gold nanoparticles have catalytic properties for reducing 4-nitrophenol to 4-aminophenol. By degrading the two dyes methyl orange and congo red in the presence of nano catalysts, the photocatalytic activity of synthesized nanoparticles has been assessed.

E-Waste: a Concise Update on Global Movement, Impacts, Management, and Site Remediation

The rapid rise of electronic waste (e-waste) worldwide has become a public health concern. Wealthy countries are disposing of their e-waste to other countries taking advantage of their less stringent environmental laws and regulations. China used to receive large amounts of e-waste through Hong Kong (a free port) but banned the entry of e-waste in 2013. Salvaging or recycling different parts of the e-waste using primitive and uncontrolled techniques generated a wide range of toxic chemicals (mainly heavy metals and persistent organic pollutants). Most studies concerning the environmental and health impacts of the emitted toxic chemicals were conducted in China. The principal aim of this short article is to review the various environmental problems and health impacts of e-waste recycling, policies, management, and remediation of contaminated sites. Out of the primitive methods used for recycling, the two most destructive ones causing harm to the environment and human health are (1) Open-burning of e-waste for disposing of the salvaged e-waste and (2) Acid-stripping of electronic boards for collecting precious metals (gold, silver, platinum). There is sufficient evidence showing the associations between the toxic chemicals in different media (i.e., water, soil/sediment, air) and local food items (i.e., fish, meat, vegetables), linking with body burdens (hair, milk, placenta) of workers and residents. The epidemiological data further demonstrated the abrupt rise of several significant diseases (i.e., respiratory disease, cardiovascular disease, malignant tumors) in Taizhou (China), one of the two e-waste recycling sites. Effective policies and vigorous enforcement in managing e-waste are essential. International cooperation is necessary to prohibit the transboundary movement of e-waste. Sites contaminated by e-waste recycling contain incredibly high concentrations of toxic pollutants, which should be removed using excavation, degradation (via microbes, nanoparticles, biochar), soil washing, etc. Planting appropriate plants with associated rhizospheric microbes would achieve longer-term stability.

A Bayesian hierarchical model for the inference between metal grade with reduced variance: Case studies in porphyry Cu deposits

Ore sorting is a preconcentration technology and can dramatically reduce energy and water usage to improve the sustainability and profitability of a mining operation. In porphyry Cu deposits, Cu is the primary target, with ores usually containing secondary ‘pay’ metals such as Au, Mo and gangue elements such as Fe and As. Due to sensing technology limitations, secondary and deleterious materials vary in correlation type and strength with Cu but cannot be detected simultaneously via magnetic resonance (MR) ore sorting. Inferring the relationships between Cu and other elemental abundances is particularly critical for mineral processing.The variations in metal grade relationships occur due to the transition into different geological domains. This raises two questions - how to define these geological domains and how the metal grade relationship is influenced by these geological domains. In this paper, linear relationship is assumed between Cu grade and other metal grades. We applies a Bayesian hierarchical (partial-pooling) model to quantify the linear relationships between Cu, Au, and Fe grades from geochemical bore core data. The hierarchical model was compared with two other models - ‘complete-pooling’ model and ‘no-pooling’ model. Mining blocks were split based on spatial domain to construct hierarchical model. Geochemical bore core data records metal grades measured from laboratory assay with spatial coordinates of sample location. Two case studies from different porphyry Cu deposits were used to evaluate the performance of the hierarchical model. Markov chain Monte Carlo (MCMC) was used to sample the posterior parameters. Our results show that the Bayesian hierarchical model dramatically reduced the posterior predictive variance for metal grades regression compared to the no-pooling model. In addition, the posterior inference in the hierarchical model is insensitive to the choice of prior. The data is well-represented in the posterior which indicates a robust model. The results show that the spatial domain can be successfully utilised for metal grade regression. Uncertainty in estimating the relationship between pay metals and both secondary and gangue elements is quantified and shown to be reduced with partial-pooling. Thus, the proposed Bayesian hierarchical model can offer a reliable and stable way to monitor the relationship between metal grades for ore sorting and other mineral processing options.

Determination of trace elements in ibuprofen drug products using microwave-assisted acid digestion and inductively coupled plasma-mass spectrometry

Trace elements are found in most drugs as a result of the drug formulation and drug production methods. An inductively coupled plasma-mass spectrometry method for the determination of 24 trace elements (Mg, Ti, V, Cr, Mn, Cu, Fe, Co, Ni, Zn, As, Se, Mo, Ru, Rh, Pd, Ag, Cd, Sb, Ba, Ir, Pt, Au, and Pb) in solid ibuprofen tablets was established in relation to the ICH Q3D(R1) guideline, to evaluate the possibility of linking trace elemental profiles to drug formulation strategies, and to differentiate between drug products based on the trace elemental profiles. Ten European ibuprofen drug products were evaluated (n=3). The sample preparation was performed by microwave-assisted acid digestion using only 10 mg of homogenized sample and 900 μL of a mix of 65% HNO3, 37% HCl, and 30% H2O2. Solid residuals primarily composed of insoluble SiO2 excipients were removed by centrifugation. Only concentrations of Mg, Fe, Ti, Mn, Cr, and Ni were detected above the limits of detection and did not exceed the ICH Q3D(R1) guideline permitted daily exposure limits. The trace elemental profiles were evaluated through principal component analysis. Three principal components describing 96% of the variance were useful in grouping the ibuprofen drug products, and the detected trace elemental remnants could be related to drug formulation and drug production strategies. An in-house quality control material was used in lack of certified reference materials and was in combination with spike recoveries used for method validation. Good spike recoveries (94–119%) were obtained for all measured trace elements except Mg. Mg showed acceptable spike recoveries (75–155%) for mid and high-spike concentrations, but poor recoveries (30–223%) were detected with low spike concentrations in spike matrices containing high amounts of Mg. Overall, the method is suggested applicable for solid drugs containing insoluble SiO2 excipients and drugs comparable to ibuprofen.

Bayesian optimization of periodic multilayered slabs for passive absorptivity control

A vanadium dioxide (VO2) film grown on a titanium oxide crystal shows a metal–insulator transition at room temperature with drastically changed optical properties. A multilayered slab with a sub-micron scale VO2 film was proposed to utilize its unique properties for passive intensity control of sunlight absorption and radiative cooling. Its optimal geometries were numerically explored using the Bayesian optimization (BO) method. BO was applied for three types of multilayered slabs, those having one, two, or three isolated slabs of different widths. For each type of multilayered slab, BO could optimize geometric variables with practical calculation times considering the total number of possible combinations of variables, which is subsequently referred to as the total number of candidates. Optimization results revealed that two isolated slabs had the most suitable spectral absorptivity in both hot and cold environments. The infrared absorptivity of the double slab was kept low in cold conditions to suppress radiative cooling. However, the double slab exhibited good radiative cooling performance under hot conditions. Electromagnetic energy density surrounding the slab illustrated that metallic VO2 and gold placed in a parallel manner excited the coupled mode of surface plasmon polaritons to enhance absorptivity. Radiative cooling faded for the triple slab because each slab could couple with radiation propagating only across a portion of the cross-sectional area. Through three BO trials, improvement of the VO2 visible reflectivity was recognized as a future issue for further development of passive sunlight absorption control.

METAL DETECTOR STUDY

Treasure hunting is one of the things that people have been interested in and engaged in for many years. Because land is a treasure and extremely important for human life. The land provides us with food and nourishment. Without land and water, there would certainly be no life. People and societies have always relied on land. It was like that in the past and it is like that today. The world has been struggling with wars and social problems for many years. In ancient times, metals such as gold were much more valuable and were even used as money at some point. For this reason, ancient peoples, tribes, and states had a lot of physical gold and similar precious metals. During the war, these precious metals were hidden in the ground in response to the risk of theft or loss, and this was symbolized by certain maps and signs. However, it was not always possible to return to the lands abandoned during social unrest and wars. For this reason, the gold remained in the places where it was buried and has somehow survived to this day in existing maps and similar diagrams. For this reason, people today believe that there is gold in the soil and in certain regions, and in this sense they seriously search for treasure. Today is the age of technology. Taking advantage of technology is one of the most important rules of treasure hunting. The most important technological tools in treasure hunting are detectors. So what is detector logic? How does it work and what types of detectors are there? Let's try to explain this in the article.The most commonly used type of detector is metal detectors. The logic of the metal detector is based on the electronic working principle. These types of detectors work according to the logic of receiving and sending electromagnetic waves. These devices send certain electromagnetic waves to the area to be searched and scanned. When it detects a metal object, it generates a current. This generated current affects the coils and some signal changes start to warn. This generated current reaches the speaker through sound systems and warns the person. Briefly speaking, the logic of the detector can be explained as follows. Different types of metal detectors are also used in this field. One of them is Bfo type detectors. It has a search coil and a single coil at the end. If the coil approaches any metal, the frequency changes and is compared with other frequencies. There are two types of detectors: 2 transistors 1 integrated and 7 transistors. The first has two coils at the search end. And this type of detector is sensitive to the signal. One of the coils is receiving and the other is transmitting. Here again, the collected frequencies reach the coils and the sound is transmitted to the speaker as current. The user receives alerts and directs his work here. Another has a working system that is sensitive to the signal phase. Another different type of detector is the detector based on the pulse system. The logic of the detector in this system is slightly different. There is only one coil in the search coil. A high current pulse is supplied to this coil for a short period of time. This creates a high magnetic field around. After finishing the conversion, it scans the surroundings and sends a signal if it detects something. If there is metal, it makes a loud sound and in this way the seeker works in a certain direction. Keywords: Working principle of metal detector, types of metal detector, IB induction balance detector, PI shock induction detector.

Hafnium (Hf)-Chelating Porphyrin-Decorated Gold Nanosensitizers for Enhanced Radio-Radiodynamic Therapy of Colon Carcinoma.

X-ray-induced radiodynamic therapy (RDT) that can significantly reduce radiation dose with an improved anticancer effect has emerged as an attractive and promising therapeutic modality for tumors. However, it is highly significant to develop safe and efficient radiosensitizing agents for tumor radiation therapy. Herein, we present a smart nanotheranostic system FA-Au-CH that consists of gold nanoradiosensitizers, photosensitizer chlorin e6 (Ce6), and folic acid (FA) as a folate-receptor-targeting ligand for improved tumor specificity. FA-Au-CH nanoparticles have been demonstrated to be able to simultaneously serve as radiosensitizers and RDT agents for enhanced computed tomography (CT) imaging-guided radiotherapy (RT) of colon carcinoma, owing to the strong X-ray attenuation capability of high-Z elements Au and Hf, as well as the characteristics of Hf that can transfer radiation energy to Ce6 to generate ROS from Ce6 under X-ray irradiation. The integration of RT and RDT in this study demonstrates great efficacy and offers a promising therapeutic modality for the treatment of malignant tumors.

Efficiency of Low-Carbon Technologies Implementation at Non-Ferrous Metallurgy Enterprises under the Conditions of Carbon-Regulation Development in Russia

Carbon markets are highly relevant to the need to regulate man-made greenhouse gas emissions. As the world faces the dangerous effects of global warming, reducing greenhouse gas emissions has become a critical priority for governments, corporations and individuals around the world. Carbon markets offer a way to incentivize and encourage emissions reductions and facilitate a smooth transition to a low-carbon economy. Low-carbon development is possible by building transparent and understandable organizational and economic conditions for the operation of carbon regulation. This article considers the feasibility of introducing energy-efficient technologies at Polymetal International PLC enterprises located in Khabarovsk region, engaged in the mining and processing of non-ferrous and precious metals (gold, silver and copper) in light of the country’s growing attention to the regulation of carbon dioxide emissions. The objective of this study is to model the organizational and economic conditions of the carbon market and estimate the economic and climate outcomes from the implementation of energy-efficient technologies at Polymetal International PLC. This study analyzes the current energy-consumption structure of non-ferrous metallurgy enterprises in Russia and identifies potential areas for the use of energy-efficient technologies. An important aspect is the assessment of government policies and incentives that could facilitate the introduction of low-carbon technologies. It is important to assess the impact of prospective carbon-management plans in Russia on the economic performance of steel companies. The results of this study suggest that the introduction of low-carbon technologies has the potential to significantly reduce energy consumption, lower operating costs and reduce carbon dioxide emissions from non-ferrous metal companies in Russia. However, the successful implementation of these technologies will require significant investment, stakeholder cooperation and political support from the Russian government.

Electronic cross section, stopping power and energy-loss straggling of metals for swift protons, alpha particles and electrons

Understanding and quantifying the electronic inelastic interactions of swift ions and electrons in metals is fundamental for many applications of charged particle beams. A common theoretical approach is moreover desirable for the case of both types of projectiles, as large numbers of secondary electrons arise as the result of ion interaction with metals. The electronic cross section, stopping power and energy-loss straggling resulting from the interaction of swift protons, alpha particles and electrons when moving through the metals aluminum, iron, copper, molybdenum, platinum and gold, are calculated theoretically for a wide energy range of the projectiles. The model is based on the dielectric formalism, which realistically accounts for the excitation spectrum of each metal through the Mermin Energy-Loss Function–Generalized Oscillator Strength (MELF-GOS) methodology. The impact of the complexity of the excitation spectrum of each metal (encompassing interband transitions and collective excitations), as well as the different sources of (sometimes conflicting) optical data is analysed in detail. Specific interactions are considered for each projectile, such as electron capture/loss and electron cloud polarisation for ions, and indistinguishability, exchange and low-energy corrections for electrons. An estimate of possible contributions of surface excitations to the interaction probabilities of low energy electrons is given. Comparison of our results with a large collection of available experimental data shows good agreement. As a practical and useful outcome of the work, we provide analytical expressions fitting all our calculated quantities, which can be applied for simulation or comparison purposes.

High refractive index sensing highly sensitive and low loss SPR sensor based on hollow-core D-shaped optical fiber

A hollow-core D-shaped optical fiber-based surface plasmon resonance (SPR) sensor for low-loss and highly sensitive liquid analytes detection is theoretically investigated. The gold (Au) metal nanolayer is coated on the cladding etched D-shaped flat surface to develop the plasmonic effect. The nanolayer coating on the outer flat surface is very easy compared to the inside hollow-core, so our hollow-core sensor manufacturing is too easy compared to other hollow-core refractive indices (RIs) detection sensors. The resonance effect between analytes filled fundamental guided core mode and surface plasmon polariton mode of the D-shaped hollow-core optical fiber sensor is used to obtain the detections of analytes RIs variations. We have found good linear results ([Formula: see text]) in analytes RIs versus resonance wavelength for gold layers thicknesses for the analytes RIs range of 1.45–1.52. This hollow-core D-shaped optical fiber sensor achieves the maximum wavelength sensitivity of 23500[Formula: see text]nm RIU[Formula: see text] and a corresponding resolution of [Formula: see text] RIU. We have obtained the maximum figure of merit (FOM) of 228 1/RIU. The proposed sensor may be highly active in detecting the biological and chemical liquid analytes.

Biogenic Synthesis of Gold Nanoparticles using Bark Extract of Bauhinia variegata: Antibacterial and in vitro Anticancer study

Our study revealed the biological synthesis of gold nanoparticles (AuNPs) using aqueous bark extract of plant named Bauhinia variegata (Kaanchnar). Biomolecules present in the plants act as a reducing and capping agent. In this reduction reaction, gold (III) metal was reduced by biomolecules present in plants leading to formation of AuNPs. Biosynthesized AuNPs were characterized by spectral analysis (XRD, FTIR, UV-visible) and imaging microscopy. Antibacterial study of the biosynthesized AuNPs was examined against Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria using agar well diffusion method and AuNPs exhibited an excellent inhibition zone against mentioned bacteria. In vitro anticancer study of AuNPs was performed on MCF-7 cell line. Compared to standard drug, AuNPs exhibited potent anticancer activity with the IC50 value 15.55 μg/ml.